MQ3 sensor code

Projects Programming
1 
#include <Adafruit_Fingerprint.h>
#include <SoftwareSerial.h>
#include <Wire.h>
#include <MQUnifiedsensor.h>
#include <LiquidCrystal_I2C.h>

SoftwareSerial mySerial(10, 11);
Adafruit_Fingerprint finger(&mySerial);
MQUnifiedsensor alcoholSensor(A0, A1);
LiquidCrystal_I2C lcd(0x27, 16, 2);

const int powerPin = 13;

void setup() {
  Serial.begin(9600);
  finger.begin(57600);
  lcd.begin(16, 2);
  lcd.print("Place finger...");
}

void loop() {
  if (finger.fingerPresent()) {
    lcd.clear();
    lcd.print("Finger detected");

    if (finger.verify()) {
      lcd.clear();
      lcd.print("Fingerprint matched");

      float alcoholConcentration = alcoholSensor.read();
      lcd.setCursor(0, 1);
      lcd.print("Alcohol: " + String(alcoholConcentration, 2)); 

      if (alcoholConcentration >= 0.03) {
        lcd.clear();
        lcd.print("Power off");
        digitalWrite(powerPin, LOW);
        delay(1000);
        digitalWrite(powerPin, HIGH);
      }
    } else {
      lcd.clear();
      lcd.print("Fingerprint not matched");
    }

    delay(2000);
  } else {
    lcd.clear();
    lcd.print("Place finger for enrollment");
    finger.addModel();
    delay(2000);
  }
}

when I compile this code, error like this "Compilation error: conversion from 'const uint8_t {aka const unsigned char}' to 'String' is ambiguous"
please solve this problem OTL

2

Your question is more than likely not related to a problem with the IDE; hence moved to a more suitable location on the forum.

I'm not sure but see if changing

lcd.print("Alcohol: " + String(alcoholConcentration, 2));

to

lcd.print("Alcohol: ");
lcd.print(alcoholConcentration, 2);

solves the issue.

PS

There is not such a thing; in future please post the complete error message using code tags; IDE 1.x (where you posted this) gives a button "copy error messages" at the right above the output window to make life easy for you; the only thing it does not do is adding the code tags.

3

C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:9:37: error: conversion from 'const uint8_t {aka const unsigned char}' to 'String' is ambiguous
In file included from C:\Users\���¿�\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:232:0,
from C:\Users\���¿�\AppData\Local\Temp\arduino\sketches\CBEFCE95EFD67073B85F38719F1EAF5C\sketch\sketch_nov23a.ino.cpp:1:
C:\Users\���¿�\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/WString.h:61:2: note: candidate: String::String(const __FlashStringHelper*)
String(const __FlashStringHelper str);
^~~~~~
C:\Users\���¿�\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/WString.h:61:2: note: conversion of argument 1 would be ill-formed:
C:\Users\���¿�\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/WString.h:59:2: note: candidate: String::String(const char)
String(const char *cstr = "");
^~~~~~
C:\Users\���¿�\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/WString.h:59:2: note: conversion of argument 1 would be ill-formed:
In file included from C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:4:0:
C:\Users\���¿�\Documents\Arduino\libraries\MQUnifiedsensor\src/MQUnifiedsensor.h:16:5: note: initializing argument 1 of 'MQUnifiedsensor::MQUnifiedsensor(String, float, int, int, String)'
MQUnifiedsensor(String Placa = "Arduino", float Voltage_Resolution = 5, int ADC_Bit_Resolution = 10, int pin = 1, String type = "CUSTOM MQ");
^~~~~~~~~~~~~~~
C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino: In function 'void loop()':
C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:22:14: error: 'class Adafruit_Fingerprint' has no member named 'fingerPresent'; did you mean 'fingerSearch'?
C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:26:16: error: 'class Adafruit_Fingerprint' has no member named 'verify'
C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:30:50: error: 'class MQUnifiedsensor' has no member named 'read'
C:\Users\장태영\AppData\Local\Temp.arduinoIDE-unsaved20231023-26684-lk55mw.ybhbj\sketch_nov23a\sketch_nov23a.ino:51:12: error: 'class Adafruit_Fingerprint' has no member named 'addModel'; did you mean 'loadModel'?

exit status 1

Compilation error: conversion from 'const uint8_t {aka const unsigned char}' to 'String' is ambiguous

4

This is all that error.
and I try using this code

lcd.print("Alcohol: ");
lcd.print(alcoholConcentration, 2);

but it doesn't work
can you help me please..?
really need someone help

5

Explain what that means. What did you expect to happen, and what happened instead?

6

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